Help Tuning 6.2L 6L80E Its retarding timing 0 knock

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Originally Posted by 400ss

From the internal speed sensor the 6L80E has,, internal vss sends to TCM, TCM sends the speed to the ECM using OSS wire.

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Ok...

so this means the TCM believes VSS to be based on internal gear ratio and axle ratio, and does not know about transfer case ratio... what is the transfer case ratio (in 4LOW)...?

The transfer case ratio would make the engine RPM be higher for the same MPH... or the MPH be lower for the same RPM... so this means the WOT MPH parameter is not being met.

Gear Ratio for the NP231 is 2.72:1

ok so thats the problem. but if a changue the MPH to work on 4Low it wont work without 4Low right??

What happen if i set all the WOT shift speeds to 10 mph and set the desired rpms?

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Originally Posted by joecar

Ok...

so this means the TCM believes VSS to be based on internal gear ratio and axle ratio, and does not know about transfer case ratio... what is the transfer case ratio (in 4LOW)...?

The transfer case ratio would make the engine RPM be higher for the same MPH... or the MPH be lower for the same RPM... so this means the WOT MPH parameter is not being met.

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Quote:

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Originally Posted by 400ss

Gear Ratio for the NP231 is 2.72:1

ok so thats the problem. but if a changue the MPH to work on 4Low it wont work without 4Low right??

What happen if i set all the WOT shift speeds to 10 mph and set the desired rpms?

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If you make the MPH low and set the RPM to shift, this is good.